As far as I know (from last year) Diezel were/are only avail. from the distributor in North London. Get in touch and they book studio time for you to try.
Problem with UK is everything is soooooooooo spread out.
This makes an amp quest just that, a bloody quest!
You may wanna factor into the equation where you will be using the amp. Gigging or just at home or gig and home.
Some amps sound YUCK at home levels (unless you live on an estate and if you are 15yo and have 1,500 or more to spend maybe you do :)).
Also, for that kinda dosh (if it wer me) I would look at some 'arguably' better made amps also. NOT saying any of those listed are bad but certainly most are mass produced and not the best quality build wise.